Bicycle Mechanics - question about evolution of wheels: 7 to 8 spd

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sunburst
02-23-09, 01:17 AM
Saw some mavic wheels on cl this weekend and the seller sent me photos, and a description.
Rims: Mavic "Open 4 CD"
Hubs: Shimano 600
Freewheel(?) Dura-ace hyperglide 8-speed

Oh yeah, one broken/missing spoke in front, and he's asking $100 - sounds like a lot to me. But I'm curious about wheel evolution anyway.

Question 1) By the photos, they appear to have a 8-spd freewheel. Does hyperglide indicate a freewheel? Since I have one wheel with a 7-spd freewheel and another with a 7-spd freehub/cassette, I assumed at 8-speeds everyone would have transitioned to freehubs - yes/no?

Question 2) can I assume anything about the rear spacing of this 8-spd? like 126? Although now that I ask, I know my 7-spd touring bike has 130+ rear dropout spacing. The seller is explaining things is very simple terms like: "the thing that hold the spokes" when he means the hub, so I didn't what to go back and forth asking him to measure things.

Question 3) I have a Shimano 600 6-spd freewheel and was wondering if I could throw it on there in place of the 8-spd in an attempt to make the wheels would work with my existing RD. Sound reasonable? The candidates for this wheelset are all mid-70 to late-80's machines, and I believe all with 126 spacing.


meb
02-23-09, 03:48 AM
Saw some mavic wheels on cl this weekend and the seller sent me photos, and a description.
Rims: Mavic "Open 4 CD"
Hubs: Shimano 600
Freewheel(?) Dura-ace hyperglide 8-speed

Oh yeah, one broken/missing spoke in front, and he's asking $100 - sounds like a lot to me. But I'm curious about wheel evolution anyway.

Question 1) By the photos, they appear to have a 8-spd freewheel. Does hyperglide indicate a freewheel? Since I have one wheel with a 7-spd freewheel and another with a 7-spd freehub/cassette, I assumed at 8-speeds everyone would have transitioned to freehubs - yes/no?

Question 2) can I assume anything about the rear spacing of this 8-spd? like 126? Although now that I ask, I know my 7-spd touring bike has 130+ rear dropout spacing. The seller is explaining things is very simple terms like: "the thing that hold the spokes" when he means the hub, so I didn't what to go back and forth asking him to measure things.

Question 3) I have a Shimano 600 6-spd freewheel and was wondering if I could throw it on there in place of the 8-spd in an attempt to make the wheels would work with my existing RD. Sound reasonable? The candidates for this wheelset are all mid-70 to late-80's machines, and I believe all with 126 spacing.

Hyperglide debuted after freehubs. Early Shimano freehubs were Uniglide. Hyperglide debuted on cassettes. Some 6 and 7 speed Shimano freewheels were later redesigned with Hyperglide teeth. IRC recently started making 5 speed Hyperglide freewheels. 8 Speed freewheels existed, but were rare and excess spacing between the hub bearing and the right droppout made them prone to axle failure-much more so than the 126 and 120mm dropout freewheels.

8 speed is 130mm spacing on road bikes.

Bill Kapaun
02-23-09, 03:50 AM
Hyper Glide as per Sheldon-
"A system of ramps (http://sheldonbrown.com/gloss_ra-e.html#ramp) and special-shaped teeth on Shimano (http://sheldonbrown.com/gloss_sa-o.html#shimano) rear sprockets (http://sheldonbrown.com/gloss_sp-ss.html#sprocket) that permits much smoother shifting than older systems.".

I don't think Shimano made an 8 speed FW.

I'm running an 8 speed on 126 spacing. I think my OLD is actually about 128 after transplanting an 8 speed FH body to a 7 speed system.
As far as using the RDER, I'm using the stock "Deer Head" on my 86 Rockhopper.
A lot depends on the travel AND WHERE the travel is.
On a different bike,I transplanted a 7 speed FW in place of a 6 speed. I had to add a bit of spacing to the drive side to get the RDER to reach the smallest cog. I had "oodles" of extra travel past the largest cog. It WAS tempting to just bend the drop out/hangar.


meb
02-23-09, 04:37 AM
Hyper Glide as per Sheldon-
"A system of ramps (http://sheldonbrown.com/gloss_ra-e.html#ramp) and special-shaped teeth on Shimano (http://sheldonbrown.com/gloss_sa-o.html#shimano) rear sprockets (http://sheldonbrown.com/gloss_sp-ss.html#sprocket) that permits much smoother shifting than older systems.".

I don't think Shimano made an 8 speed FW.

I'm running an 8 speed on 126 spacing. I think my OLD is actually about 128 after transplanting an 8 speed FH body to a 7 speed system.
As far as using the RDER, I'm using the stock "Deer Head" on my 86 Rockhopper.
A lot depends on the travel AND WHERE the travel is.
On a different bike,I transplanted a 7 speed FW in place of a 6 speed. I had to add a bit of spacing to the drive side to get the RDER to reach the smallest cog. I had "oodles" of extra travel past the largest cog. It WAS tempting to just bend the drop out/hangar.

I'd seen an 8 speed Shimano freewheel advertised on ebay-it looked like a freewheel rather than a cassette-so they may have had a short market life-or maybe the seller had the brand wrong.
The OP mentioned 600 hubs (didn't specify freewheel/freehub brand)-they would be compatible with Sachs freewheels. I have a couple of Sachs 8 speed freewheels and 1 Falcon and 1 Epoch in 8 speed.

I'm inclined to believe the wheels the OP has in question are more likely to be freehubs than freewheel-the 600 group existed after freehubs debut and 8 speed freewheels are pretty rare.

The 600 group was eventually renamed Ultegra.
The price sounds high given spoke damage.


Here's Sheldon Brown's article on the history of freehubs:
http://www.sheldonbrown.com/k7.html

HillRider
02-23-09, 06:07 AM
I'd seen an 8 speed Shimano freewheel advertised on ebay-it looked like a freewheel rather than a cassette-so they may have had a short market life-or maybe the seller had the brand wrong.
AFAIK, Shimano never made 8-speed freewheels. In fact, they only make a couple of 7-speed freewheel sizes.

Sun Race 8-speed freewheels are still available but 8-speed freewheel hubs are a poor bet due to the excessive length of unsupported axle.

tatfiend
02-23-09, 11:50 AM
Regarding question 3:

Normally 6 speed road bike were 126mm dropout width as I recall. The rear wheel will almost certainly be 130mm. A steel frame can be sprung enough to install the 8 speed wheel but not aluminum or CF. At least considered poor idea with the latter two frame materials.

Gonzo Bob
02-23-09, 11:51 AM
If the cogs are Dura-Ace HyperGlide 8-speed, it is a cassette hub (aka freehub), not a freewheel hub. It should also measure 130mm.

operator
02-23-09, 01:16 PM
It WAS tempting to just bend the drop out/hangar.

Good thing you didn't, it wouldn't have worked.

Jeff Wills
02-23-09, 06:49 PM
AFAIK, Shimano never made 8-speed freewheels. In fact, they only make a couple of 7-speed freewheel sizes.


Correct-ish. Top-quality Shimano 7-speed freewheels were available in the late '80's in Dura-Ace and Santé versions, which accepted most of the same cogs as the Shimano 600 freewheels of the same era. If you wanted a 12-34 7-speed freewheel, it could be built, but it would be a custom job.

(I worked at Euro-Asia Imports back then. I custom-built lots of freewheels.)

Later Shimano 7-speed Hyperglide freewheels are still available:
http://sheldonbrown.com/harris/freewheels.html#7